79 lines
1.7 KiB
Python
79 lines
1.7 KiB
Python
"""
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实例：
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汤宝宝一时想不开，当了房产中介。
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一旦片区内有房东发布了新房源信息，他就会第一时间通知所有潜在租客。
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"""
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from abc import ABC, abstractmethod
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# 抽象观察者类
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class Observer(ABC):
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@abstractmethod
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def update(self):
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pass
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# 抽象目标接口
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class Subject(ABC):
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@abstractmethod
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def attach(self, observer: Observer):
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pass
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@abstractmethod
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def detach(self, observer: Observer):
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pass
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@abstractmethod
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def notify(self):
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pass
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# 具体目标类
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class HousingAgency(Subject):
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def __init__(self):
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self._observers = []
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def attach(self, observer: Observer):
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self._observers.append(observer)
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def detach(self, observer: Observer):
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self._observers.remove(observer)
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def notify(self):
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print("房产中介通知了所有租客。")
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for observer in self._observers:
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observer.update()
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# 具体观察者类
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class Tenant(Observer):
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def __init__(self, name: str):
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self.name = name
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def update(self):
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print(f"租客{self.name}收到房源更新通知！")
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if __name__ == "__main__":
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print("============= 观察者模式 =============")
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agency = HousingAgency()
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tenant1 = Tenant("小明")
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tenant2 = Tenant("小红")
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print("小红和小明订阅了房产中介的房源信息。")
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agency.attach(tenant1)
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agency.attach(tenant2)
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print("房源上新了！")
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agency.notify()
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print("-----")
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print("小红不想再接收房源信息，退订了。")
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agency.detach(tenant2)
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print("又有新房源了！")
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agency.notify()
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print("\n=========== 观察者模式结束 ===========")
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